         all-moves (get-in game [:moves player])]
     (transduce
       (map #(move-strength (:cells-strength game) converted-filter %))
-      max
-      all-moves)))
+      max all-moves)))
 
 (defn best-move
   "[SIMPLISTIC] Return the best move for a player based on:
    * The immediate gain
    * The worse immediate lost afterwards"
-  {:pre (player? player)}
+  {:pre [(player? player)]}
   [game player]
   (let [moves (get-in game [:moves player])
         others (remove #{player} players)]


(defn- compute-cell-strength
  "Compute a cell strength based on the number of walls it has"
  [board point]
  (let [neighbors (coord-neighbors point)
        walls (filter #(= :wall (get-in board % :wall)) neighbors)]


(defn ^boolean is-cell-empty?
  "Indicates whether a cell is owned by any player"
  {:pre [(or (nil? cell) (cell? cell))]} 
  [cell]
  (or (nil? cell) (= cell :empty) (= cell :wall)))

